A Numerical Study on the Light-Weight Design of PTC Heater for an Electric Vehicle Heating System

Abstract

As the market for electric vehicles grows at a remarkable rate, various models of electric vehicles are currently in development, in parallel to the commercialization of components for diverse types of power supply. Cabin heating and heat management components are essential to electric vehicles. Any design for such components must consider the requirements for heating capacity and power density, which need to reflect both the power source and weight reduction demand of any electric vehicle. In particular, design developments in electric heaters have predominantly focused on experimental values because of structural characteristics of the heater and the variability of heat sources, requiring considerable cost and duration. To meet the ever-changing demands of the market, an improved design process for more efficient models is essential. To improve the efficacy of the design process for electric heaters, this study conducted a Computational Fluid Dynamics (CFD) analysis of an electric heater with specific dimensions by changing design parameters and operating conditions of key components. The CFD analysis modeled heat characteristics through the application of user-defined functions (UDFs) to reflect temperature properties of Positive Temperature Coefficient (PTC) elements, which heat an electric heater. Three analysis models, which included fin as well as PTC elements and applied different spaces between the heat rods, were compared in terms of heating performance. In addition, the heat performance and heat output density of each analysis model was analyzed according to the variation of air flow at the inlet of the radiation section of an electric heater. Model B was selected, and a prototype was fabricated based on the model. The performance of the prototype was evaluated, and the correlation between the analysis results and the experimental ones was identified. The error rate between performance change rates was approximately 4%, which indicated that the reliability between the design model and the prototype was attained. Consequently, the design range of effective performance and the guideline for lightweight design could be presented based on the simulation of electric heaters for various electric vehicles. The fabrication of prototypes and minimum comparison demonstrated opportunities to reduce both development cost and duration.

Heating Performance Enhancement of High Capacity PTC Heater with Modified Louver Fin for Electric Vehicles

“…results of the heating performance from Kang et al when using the same geometric design variables [11]. The error was found to be 5.7%.…”

“…Heater A was the basic model of the geometric design variables used in this study. It used a plate-shaped radiator fin and a PTC element that generated heat at 172 • C [11]. Heater B used a PTC element that generated heat at 188 • C in the heat rods, and it used a modified louver shape in the radiator fin.…”

“…To ensure the reliability of the heat flow analysis, the P1 model was used to verify the independence of the meshes in Figure 5, and it was found that approximately 5.6 million meshes were appropriate considering the performance and computation speed of the computer. To ensure the reliability of the analysis model, the P1 model was also compared to the experiment results of the heating performance from Kang et al when using the same geometric design variables [11]. The error was found to be 5.7%.…”

Experimental study on the preheating efficiency of an aluminum‐rich ternary lithium‐ion battery using constant‐voltage preheating method

“…Commonly used preheating methods for lithium-ion batteries can be divided into external preheating and internal preheating according to the location of heat generation. The external preheating method usually uses external energy to generate heat for battery preheating and the energy is transferred to the battery through convection [12][13][14] or conduction [15][16][17] to increase the battery temperature. Compared with external heating, internal heating generates heat inside the battery.…”

Designs of conductive polymer composites with exceptional reproducibility of positive temperature coefficient effect: A review

“…Fascinatingly more, the CPCs, considered as smart materials, exhibit the capability of thermal response, including positive temperature coefficient (PTC) effect, negative temperature coefficient (NTC) effect and zero temperature coefficient effect, corresponding to the increase, decline and constant of resistance with elevating temperature, respectively 11–15 . For CPCs with PTC effect, the property of raising electrical resistivity upon heating endows them with a range of promising applications by performing both sensing and self‐regulating functions in the fields of automobile, spacecraft, smart building and medical equipment 16–24 …”